The Foveaux Strait oyster (OYU 5) stock assessment model was reviewed. Development of a disease sub-model to provide projections of future disease mortality will greatly improve assessments. B0 and stock reference points may be overestimated. Conceptual models of climatic, environmental, habitat, disease, and biological drivers of oyster production highlight several knowledge gaps. An understanding of disease processes and new time series data will underpin better stock projections.

The silver warehou stock assessment conducted in 2023 is described. The assessment was ultimately rejected by the Fisheries New Zealand Deepwater Working Group. The data inputs and model assumptions are described. The main problems encountered, concerning stock structure, CPUE, age data, and model specifications, and their possible solutions, are discussed.

The Spatially Explicit Fisheries Risk Assessment framework has recently been updated and applied to assess the fisheries risk to seabird populations within the New Zealand EEZ. In the current report, the approach is applied to seabirds globally in the southern hemisphere. Catchabilities were estimated from New Zealand captures. Then global fishing effort and species distributions were collated and used to assess the risk to seabirds from predicted fisheries captures throughout their range.

This report summarises the ling stock off the west coast South Island (LIN 7WC) and fishery. It describes the spatial structure of the stock, biological parameters, and trawl and longline standardised catch per unit effort (CPUE). Statistical Area 032 was reassigned to LIN 7WC based on the continuity of catch locations. The trawl and longline fishery CPUE and survey biomass showed similar patterns from 2000, with a decline from 2012. All three indices were considered in the stock assessment.

This report investigated the spatial and temporal structure of arrow squid (Nototodarus sloanii and N. gouldi) in New Zealand. Five potential stocks were defined. Estimates of growth rate were consistent with previous estimates. Spatial-temporal standardised CPUE fortnightly indices were developed and could be predicted relatively well by environmental variables. Preliminary population models showed recruitment was well estimated but initial biomass was highly uncertain.

A Management Strategy Evaluation (MSE) was conducted for hoki based on the recent (2022) stock assessment model. The MSE evaluated a set of Harvest Control Rules that specified a target biomass range and varied annual fishery catches relative to fluctuations in eastern and western stock biomass.

This report summarises the stock assessment of hake off the west coast South Island (WCSI) in HAK 7 for the 2021–22 fishing year. The index of abundance was the WCSI trawl survey. Initial spawning stock biomass was estimated as 78 870 t (95% CIs 74 140–84 810) with current status of 39% B0 (95% CIs 30–52% B0). Five-year projections showed that biomass would increase under average recruitment but would remain flat if future recruitments were low and catches were the same as the TACC.

This report summarises the WCSI hake (HAK 7) fishery with spatial structure of the stock, biological parameters, and standardised catch per unit effort (CPUE). The CPUE indices were similar for the tow-by-tow data and the daily summary data and showed a similar trend to the Sub-Antarctic trawl surveys. In general, the CPUE indices had declined over the period of fishing but had levelled off in recent years as the total catch declined.

This report presents the NIWA analysis of simulated Indian Ocean Yellowfin tuna (IOYT) data as part of the 2022–23 International Approaches and Advancements in Spatial Stock Assessment workshop programme. Two stock assessment model structures were developed and evaluated and are the focus of this report: a single area model which used the aggregated datasets, and a fleets-as-areas model.

The present project provides an update to the pāua (Haliotis iris) stock assessment for quota management area (QMA) PAU 5D and tested control rules to aimed at rebuilding catch towards the Total Allowable Commercial Catch. The findings suggested that the stock has been rebuilding and is now as likely as not to be at the interim management target. The harvest control rule from 2016 was updated to include a lag year on increases and a maximum 5% limit on year-on-year increases.

A novel spatial risk assessment framework is proposed, based on the Spatially Explicit Fisheries Risk Assessment (SEFRA) and the Sustainability Assessment for Fishing Effects (SAFE). Risk is the probability that exploitation exceeds the Impact Sustainability Threshold (IST). Exploitation is estimated from the catchability and effort, using prior information on either the catchability or the population size. It is applied to shark and turtle species with different data characteristics.

This report documents the 2022 stock assessment of red rock lobsters in CRA 2. The model was fitted to length frequency data, sex ratio data, tag-recapture growth increment data, and standardised catch-per-unit-effort indices using the lobster stock dynamics model. This stock assessment estimated generally increasing exploitation rates throughout the stock’s history. Catch cuts and a period of improved recruitment have helped the stock rebuild since the 2017 stock assessment.

This report documents the data used by the 2022 stock assessment of red rock lobsters in CRA 2. The data sets described include: catch estimates from commercial, recreational, customary, and illegal components of the fishery; standardised catch-per-unit-effort indices; standardised catch length-frequency distributions and sex ratios; tag-based growth information; and the proportion of mature females that were in berry (egg-bearing).

A spatial analysis of catch and effort data from the SNA 1 bottom trawl fishery was used to refine the boundary of the East Northland and Hauraki Gulf snapper stocks. For the two stock units, bottom trawl CPUE indices were derived for the spring-summer period. The two sets of CPUE indices were included in the 2023 stock assessment of SNA 1.

A fully integrated stock assessment is presented for HOK 1 modelled with two stocks (western and eastern) and with fish residing in four regions. The western stock is estimated to be lower than the eastern stock, with biomass expected to be 25–43% B0 in 2027 under current catch levels for the western stock and 46–55% B0 for the eastern stock. A simpler model with one stock and one region estimated current biomass to be 37–45% B0 in 2022. Target range for hoki is 35–50% B0.

Characterisation and CPUE (catch-per-unit-effort) analysis for SCI 1 (Bay of Plenty) and SCI 2 (Hawke Bay-Wairarapa) scampi (Metanephrops challengeri). Scampi live in burrows and variability in emergence rates impact the relationship between CPUE and abundance. SCI 1 index increased from 2016 to 2021. SCI 2 CPUE generally declined from 2015 to 2021. The CPUE indices were accepted by the New Zealand Fisheries Deepwater Working Group as valid for tracking scampi biomass for use in the stock assessment.